1. Field
The present disclosure relates generally to systems and methods for generating data by a computer simulation of a flow of fluid over a surface, and more particularly to systems and methods for generating such data for sub-areas of a surface from data generated for a number of points on an area of the surface.
2. Background
Computational fluid dynamics is a branch of fluid dynamics. Computational fluid dynamics uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. For example, computers may be used to perform the calculations required to simulate the interaction of liquids and gasses with a surface defined by boundary conditions. The result of these calculations may be data for a number of points in an area of the surface. For example, the area of the surface may be a two-dimensional planar area of the surface. Data generated for the number of points may include values for various properties related to fluid flow over the surface. For example, such properties may include temperature, pressure, heat flux, velocity, and other properties.
Aerodynamic heating is the heating of a solid body produced by the frictional interactions and passage of fluid about the body. Aerodynamic heating analysis may be performed by a computer using a thermal model of the body and computational fluid dynamics data describing the properties of fluid flows across the body.
Aerodynamic heating of aerospace vehicles is of particular interest. For example, aerospace vehicles may include aircraft and spacecraft that are designed to reenter the atmosphere. Aerodynamic heating occurs when air passes over an aerospace vehicle during vehicle transit, ascent, descent, and reentry. Aerodynamic heating of an aerospace vehicle is a function of various factors. For example, aerodynamic heating of an aerospace vehicle is a function of such factors as reentry angle, speed, air density, thermal protection system material properties, vehicle configuration, and other factors.
Depending on the vehicle configuration and thermal protection system material properties, aerodynamic heating typically increases as the air increases in density and as the air passes more quickly over the vehicle. The increase in the speed at which air passes over the vehicle typically occurs as the speed of the vehicle increases. Aerodynamic heating temperatures encountered during aerospace vehicle transit, ascent, descent, and reentry can range between approximately 600 degrees Celsius (“° C.”) and approximately 1930° C., approximately between 600° F. and 3500° F.
The degree of aerodynamic heating experienced by an aerospace vehicle may affect various characteristics of the vehicle. For example, aerodynamic heating considerations may affect the performance of a vehicle, which types of thermal protection system configurations and materials are needed for the vehicle, how often inspections and maintenance are needed, and whether the vehicle should be reconfigured, repaired, and/or replaced.
The effects of aerodynamic heating on a vehicle structure may be controlled to within acceptable limits through the use of a thermal protection system. For example, a thermal protection system may be used on an aerospace vehicle that travels at supersonic, hypersonic, exo-orbital, and exo-atmospheric speeds. A thermal protection system also may be used on a spacecraft that reenters the atmosphere.
For example, a thermal protection system for a space shuttle includes a barrier to protect the space shuttle from aerodynamic heating when the space shuttle renters the atmosphere. The temperatures encountered by the space shuttle during reentry may be about 1650° C. degrees or more. The thermal protection system for the space shuttle includes a material that covers the surface of the space shuttle that is exposed to air during reentry. The thermal protection system may be implemented using various materials. For example, such materials may include one or more of an integrated and integral ceramic matrix composite material (CMC), a polymeric matrix composite material (PMC), and such materials that are clad with ablative and high-temperature coating materials.
In the space shuttle example, the thermal protection system takes the form of tiles that are attached to the surfaces of the space shuttle that are exposed to heating during reentry. For example, these tiles may be located on the lower surface of the space shuttle. Thermal protection system tiles also may be located at other suitable places on the space shuttle. The tiles on the space shuttle are made of an insulating material known to those having knowledge in the relevant arts to be a silca glass fiber material. The many types and configuration of such tiles absorb and radiate heat while minimizing heat load conduction to the aluminum airframe.
Unintended features or anomalies may occur in an aerospace vehicle thermal protection system. For example, such unintended features or anomalies may occur in the thermal protection system tiles, in the materials used to attach the tiles to the space shuttle surface, and in the materials used to seal and fill gaps and channels between the tiles. These unintended features or anomalies may occur as nicks, dings, or scrapes in the tiles and/or as foreign objects embedded in or between the tiles. Such unintended features or anomalies may arise or occur during pre-flight preparation or during operation of aerospace vehicles such as the space shuttle. Such undesirable features or anomalies may affect the aerodynamic characteristics and performance of the thermal protection system. Similar issues may arise in other types of thermal protection systems, using other types of materials, and that are used in other types of aerospace vehicles.
Accordingly, it would be advantageous to have a method and apparatus, which takes into account one or more of the issues discussed above as well as possibly other issues.